Human tissue samples obtained during surgical procedures or autopsies are stored for use in future research studies, together with associated metadata. The stored tissue samples are frequently subjected to molecular studies, such as genome or transcriptome analysis. Thus far, standard practice has been to preserve the tissue sample and then store it as a block of tissue, in a storage facility loosely referred to as a “biobank”. If a researcher or clinician later wished to examine a particular phenotypic or genotypic feature within a tissue block, the whole block of tissue would have to be retrieved from storage, and the tissue sectioned to obtain the region of the tissue block of interest. In many cases this region is only a small portion of the tissue in the block, so the remainder of the tissue is wasted. Another modality in the practice of anatomic pathology is to cut a tissue block into sections in order to perform histochemical analysis prior to storage in the tissue depository. Each tissue section is placed on a glass slide. Some slides are analyzed with histochemical stains, but other slides, referred to as “blank slides,” are stored unstained. In order to retrieve a region of tissue of interest, it has heretofore been necessary to retrieve a blank slide and slightly stain and visualize a section of the stored tissue to determine where the region, or “boundary,” may lie. Unfortunately, staining can degrade the very molecule that would have yielded valuable information. Further, this procedure is wasteful, because tissue stored in a block must first be sectioned and some sections discarded.
Thus, it would be an advantage to have a system which stores, and is able to retrieve, a small defined microscopic region of a specimen from a specific physical location within a three-dimensional specimen block, based on known specific micro-structural phenotypic information.